Answer: 2 moles of water.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The combustion of propane is represented as :
[tex]C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)[/tex]
According to stoichiometry:
5 moles of [tex]O_2[/tex] produces = 4 moles of [tex]H_2O[/tex]
2.5 moles of [tex]O_2[/tex] will produce=[tex]\frac{4}{5}\times 2.5=2[/tex] moles of [tex]H_2O[/tex].
Thus 2 moles of water are produced by 2.5 moles of oxygen.